           [i sline] (first slines)]
       (when (or oline sline)
         (do (println (ljust OUT-WIDTH (string/replace (or oline "") "\n" ""))
-                     (when sline (str "// " i " " sline)))
+                     (if sline (str "// " i " " sline) ""))
             (recur (rest olines) (rest slines)))))))
 
 (defn emit [slines pmodel-in]


(defn -main []
  (let [smodel (read-model-file "src/cbfg/fence.cljs")
        pmodel (cvt-top-level-forms smodel)]
    (emit (:lines smodel) pmodel)))


(defn cvt-defn [name params body]
  ["func" (cvt-sym name) (rest (cvt-fn params body))])

(defn cvt-top-level-form [form]
  (let [[op name & more] form]
    [(case (str op)
      "ns" (j ["package" (cvt-sym name)])
      "defn" (j (cvt-defn name (first more) (rest more)))
      "UNKNOWN-TOP-LEVEL-FORM")
     (line-range form)]))

(defn numbered-lines [lines beg end] ; beg and end are 1-based.
  (map vector
